In drafting, the use of a T-square is common. When using a T-square, though, one hand must be kept on the square in order to stabilize and prevent movement. This becomes especially difficult when an angle must be created with other drafting tools, a 75 degree angle for example. The use of a triangle or even two triangles and the T-square becomes awkward at best. Other difficulties are encountered when the T-square is used to make vertical lines. The present apparatus provides a selectively secured T-square which solves the above noted problems.